1. Chapter 12 Anatomy and Mechanics of the Vertebral Column
Manual of Structural Kinesiology
The Trunk and Spinal Column

2. The Trunk and Spinal Column
Vertebral column – complex
24 intricate & complex articulating vertebrae
31 pairs of spinal nerves
Abdominal muscles
some sections linked by fascia & tendinous bands
do not attach from bone to bone
Many small intrinsic muscles act on head, vertebral column, & thorax
assist in spinal stabilization or respiration

3. Bones 24 articulating & 9 fused vertebrae 7 cervical (neck) vertebrae
12 thoracic (chest) vertebrae
5 lumbar (lower back) vertebrae
5 sacrum (posterior pelvic girdle) vertebrae
4 coccyx (tail bone) vertebrae
Vertebrae increase in size from cervical to lumbar region due to lower back having to support more weight

4. Bones
3 normal curves within moveable spine enable it to absorb blows & shocks
Thoracic spine curves anteriorly
Kyphosis - increased anterior concavity of thoracic curve
Cervical & lumbar spine curve posteriorly
Lordosis - increased posterior concavity of lumbar & cervical curves
Lumbar kyphosis - reduction of normal lordotic curve, resulting in a flat-back appearance
Scoliosis - lateral curvatures or sideward deviations of spine

5. Bones First 2 cervical vertebrae – Atlas (C1) Axis (C2)
Vertebrae C2 through L5 - similar architecture.

6. Joints Atlantooccipital joint Atlantoaxial joint first joint
formed by occipital condyles of skull sitting on articular fossa of the 1st vertebra
allows capital flexion & extension
Atlantoaxial joint
Atlas (C1) sits on axis (C2)
Most cervical rotation occurs here
50% of total cervical rotation

7. Bones Cervical vertebrae(C3-7) Body of all the vertebrae.
Bifid spinous process.
Transverse foramen for vertebral artery
5 to 7° of rotation each= 50% of total cervical rotation

8. Bones Thoracic vertebrae (T1-T12)
Thoracic vertebrae articulate with the ribs
Costal facets articulate with the ribs
Characteristic down sloping spinous process

9. The Trunk and Spinal Column
Bones
Lumbar vertebrae (L1-5)
Bodies of the vertebrae are largest to support weight-bearing.
Thick bulbous spinous and transverse processes
Manual of Structural Kinesiology
The Trunk and Spinal Column

10. Bones 12 pairs of ribs 7 pairs of true ribs attach directly to sternum
5 pairs of false ribs
3 pairs attach indirectly to sternum
2 pairs of floating ribs - ends are free

11. The Trunk and Spinal Column
Joints
Intervertebral disks
between & adhering to articular cartilage of vertebral bodies
annulus fibrosus - outer rim of dense fibrocartilage
nucleus pulposus - central gelatinous, pulpy substance
compressed elastic material allows compression in all directions along with torsion
become less resilient with age, injury, or improper use, resulting in a weakened annulus fibrosus
Manual of Structural Kinesiology
The Trunk and Spinal Column

12. The Trunk and Spinal Column
Joints
Intervertebral disks
herniated nucleus pulposus (herniated or “slipped” disk) – nucleus protruding through annulus resulting from substantial weakening combined with compression
protrusion puts pressure on spinal nerve root, causing radiating pain, tingling, numbness, and/or weakness in lower extremity
Manual of Structural Kinesiology
The Trunk and Spinal Column

13. The Trunk and Spinal Column
Movements
Spinal flexion
anterior movement of spine; in cervical region the head moves toward chest; in lumbar region the thorax moves toward pelvis
Manual of Structural Kinesiology
The Trunk and Spinal Column

14. The Trunk and Spinal Column
Movements
Spinal extension
return from flexion or posterior movement of spine; in cervical spine, head moves away from the chest & thorax moves away from pelvis
Manual of Structural Kinesiology
The Trunk and Spinal Column

15. The Trunk and Spinal Column
Movements
Lateral flexion (left or right)
sometimes referred to as side bending; head moves laterally toward the shoulder & thorax moves laterally toward pelvis
Reduction
return movement from lateral flexion to neutral
Manual of Structural Kinesiology
The Trunk and Spinal Column

16. The Trunk and Spinal Column
Movements
Spinal rotation (left or right)
rotary movement of spine in horizontal plane; chin rotates from neutral toward shoulder & thorax rotates to one side
Manual of Structural Kinesiology
The Trunk and Spinal Column

17. Trunk & Spinal Column Muscles
Abdominal wall muscles do not go from bone to bone but attach into an aponeurosis (fascia) around rectus abdominis area
external oblique abdominal, internal oblique abdominal & transversus abdominis
The Trunk and Spinal Column

18. Muscles of the Abdominal Wall
Rectus abdominis
External oblique abdominal
Internal oblique abdominal
Transverse abdominis
Manual of Structural Kinesiology
The Trunk and Spinal Column

19. Muscles of the Abdominal Wall
Rectus abdominis
External oblique abdominal
Internal oblique abdominal
Transverse abdominis
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The Trunk and Spinal Column

20. Rectus Abdominis Muscle
Both sides: lumbar flexion
Posterior pelvic rotation
Right side: weak lateral flexion to right
Left side: weak lateral flexion to left
Manual of Structural Kinesiology
The Trunk and Spinal Column

21. External Oblique Abdominal Muscle
Both sides: lumbar flexion
Posterior pelvic rotation
Right side: lumbar lateral flexion to right, rotation to left, & lateral pelvic rotation to left
Left side: lumbar lateral flexion to left, rotation to right, & lateral pelvic rotation to right
Manual of Structural Kinesiology
The Trunk and Spinal Column

22. Internal Oblique Abdominal Muscle
Both sides: lumbar flexion
Posterior pelvic rotation
Right side: lumbar lateral flexion to right, rotation to right, & lateral pelvic rotation to left
Left side: lumbar lateral flexion to left, rotation to left, & lateral pelvic rotation to right
Manual of Structural Kinesiology
The Trunk and Spinal Column

23. Transversus Abdominis Muscle
Forced expiration by pulling the abdominal wall inward
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The Trunk and Spinal Column

24. Transversus Abdominis Muscle
Stabilizes the lumbar spine in conjunction with the erector spinae muscles
Manual of Structural Kinesiology
The Trunk and Spinal Column

25. Quadratus Lumborum Muscle
Lateral flexion to ipsilateral side
Stabilizes pelvis & lumbar spine
Extension of lumbar spine
Anterior pelvic rotation
Lateral pelvic rotation to contralateral side
Manual of Structural Kinesiology
The Trunk and Spinal Column

26. Muscles that Move the Head
All originate on cervical vertebrae & insert on occipital bone of skull (capitis name)
3 anterior vertebral muscles – longus capitis, rectus capitis anterior & rectus capitis lateralis
All are flexors of head & upper cervical spine
Rectus capitis lateralis
laterally flexes head
assists rectus capitis anterior in stabilizing atlantooccipital joint
Manual of Structural Kinesiology
The Trunk and Spinal Column

27. Muscles that Move the Head
Posterior muscles
Rectus capitis posterior major & minor, obliquus capitis superior & inferior, and semispinalis capitis
All are extensors of head except obliquus capitis inferior which rotates atlas
Obliquus capitis superior assists rectus capitis lateralis in lateral flexion of head
Rectus capitis posterior major rotates head to ipsilateral side
Semispinalis capitis rotates head to contralateral side
Upper trapezius extend head & rotate its to ipsilateral side
Manual of Structural Kinesiology
The Trunk and Spinal Column

28. Muscles that Move the Head
Posterior muscles
Manual of Structural Kinesiology
The Trunk and Spinal Column

29. Sternocleidomastoid Muscles
Both sides: extension of head at atlantooccipital joint & flexion of neck
Right side: rotation to left & lateral flexion to right
Left side: rotation to right & lateral flexion to left
Manual of Structural Kinesiology
The Trunk and Spinal Column

30. Splenius Muscles (cervicis, capitis)
Both sides: extension of head (splenius capitis) & neck (splenius capitis and capitis)
Right side: rotation & lateral flexion to right
Left side: rotation & lateral flexion to left
Manual of Structural Kinesiology
The Trunk and Spinal Column

31. Muscles that Move the Head
Notice the anterior cervical spine has much less muscular development.
Manual of Structural Kinesiology
The Trunk and Spinal Column

32. Posterior Muscles of the Thorax
Involved almost entirely in respiration
Diaphragm
Responsible for breathing during quiet rest
As it contracts & flattens, thoracic volume is increased & air is inspired to equalize the pressure
When larger amounts of air are needed, as in exercise, other thoracic muscle have a more significant role in inspiration
Manual of Structural Kinesiology
The Trunk and Spinal Column

33. Posterior Muscles of the Thorax
Scalene muscles elevate first 2 ribs to increase thoracic volume
External intercostals further expand the chest
Levator costarum & serratus posterior – inspiration
Internal intercostals, transversus thoracis, & subcostales contract to force expiration
Manual of Structural Kinesiology
The Trunk and Spinal Column

34. Erector Spinae Muscles (sacrospinalis)
Iliocostalis (lateral layer)
Longissimus (middle layer)
Spinalis (medial layer)
Extension, lateral flexion, & ipsilateral rotation of spine & head
Anterior pelvic rotation
Lateral pelvic rotation to contralateral side
Manual of Structural Kinesiology
The Trunk and Spinal Column

35. Deep Muscles of the Vertebral Column
Posterior
Interspinal-intertransverse group
Intertransversarii muscles
flex vertebral column laterally
connect to transverse processes of adjacent vertebrae
Manual of Structural Kinesiology
The Trunk and Spinal Column

36. Deep Muscles of the Vertebral Column
Muscles play a major role in stabilizing the spine.
Multifidi is a major spinal stabilizer.
Segmental innervation = spinal segment misalignment inhibits this muscle .
Works in conjunction with abdominal muscles (especially transverse abdominis).
Posterior View

37. The Trunk and Spinal Column
Web Sites
Loyola University Medical Center: Structure of the Human Body
An excellent site with many slides, dissections, tutorials, etc. for the study of human anatomy
University of Arkansas Medical School Gross Anatomy for Medical Students
Dissections, anatomy tables, atlas images, links, etc.
Wheeless’ Textbook of Orthopaedics
This site has an extensive index of links to the fractures, joints, muscles, nerves, trauma, medications, medical topics, lab tests, and links to orthopedic journals and other orthopedic and medical news.
Stabilization Sensibility
A discussion on muscles of the Abdomen
Manual of Structural Kinesiology
The Trunk and Spinal Column

38. The Trunk and Spinal Column
Web Sites
Spine Universe
Information on the spine for educating the public about technologies, services, treatments and research available on spinal disorders
Become Healthy Now.com: The Spine
Anatomy and function of spine
Virtual Hospital
Numerous slides, patient information, etc.
Core Stability
The muscles of the trunk, training techniques, and exercises
Manual of Structural Kinesiology
The Trunk and Spinal Column